Precise airflow and
special ventilation systems are required to remove paint fumes and
overspray exhaust into the air from paint spray booth ventilating
systems. Fans and blowers are used to remove toxic fumes, and provide a
safe working environment without disturbing the finishing process. CBC
Blower meets these requirements by offering a variety of fans and
blowers that are constructed with the high performance ratings at very
low noise and vibration levels.
Manufacturers of Canarm fans,
Leader fans, CFC cincinnati
blowers, Delhi ventilators, Plastec blowers, combustion process
pressure blowers, vaneaxial fans, tubeaxial blowers, oven circulating
fans, fan air kits, plug ventilators, New York Blower fans, ILG
ventilators, Madok coils, Sheldons Engineering fans, Chicago Blower
pressure blowers, dayton ventilators, Cincinnati Fan blowers, Grainger
fans and blowers, side channel regenrative blowwers, blow-off
ventilators, centrifugal fans, axial blowers, combustion ventilators,
delhi fans ventilators, FRP pressure blowers, high temprature
industrial and turbo fans and blowers ventilators;
high temperature pressure blowers and high temperature plug fans; oven
fan blowers; filtered air make-up fan blowers.
The fan chart is a table
presentation of fan performance. It is one of the most useful tools
available during the fan selection process. While multi-rating tables
are convenient (see page 12), performance curves offer additional
information such as - how much reserve pressure head exists between the
design pressure and the peak static pressure, the maximum power the fan
might draw, and the efficiency of operation.
Fan curves are based on laboratory test data and are sometimes referred
to as "test curves". A typical test curve will often define the
performance parameters for a specific design and size of fan, operating
at a given speed, moving a gas of a given density. Inspection of this
graph will show that it is actually composed of four separate curves:
• Static Pressure vs. Volume Curve: This plot is the one often referred
to as the "fan curve" or "characteristic curve" because it defines all
the possible pressure-volume combinations the fan is capable of
producing given stated conditions (i.e. rpm and gas density). Note that
this curve has two regions - one marked by dashed lines and the other
by a solid line. Fans must be selected so that the design point is
located on a solid portion of the curve, preferably in an area of high
operating efficiency. Operation on the dashed portion of the curve
should be avoided as it is a zone of potentially unstable performance.
For this reason it is wise to allow some reserve between the peak
static pressure and the design pressure to compensate for a higher
resistance to flow than anticipated by the design calculation.
• Static Efficiency vs. Volume Curve: In most instances it is desirable
to have a fan perform as close to its peak efficiency as possible. The
static efficiency vs. volume curve illustrates the efficiency of fan
performance at a glance.
• Power vs. Volume Curve: This plot illustrates the power draw of the
fan for any point on the characteristic curve.
• System Curve: The system curve defines the volume flow rate versus
pressure characteristics of the system in which a fan will be
For most applications, the volume flow rate to pressure relationship is
governed by the following equation, often called the "duct law":
Once the system designer has determined the system pressure loss (P)
for one flow rate (CFM), it is very easy to calculate the corresponding
pressure loss for any other flow rate using this "law". The system
curve is not included on the performance curve when it is issued from
the fan manufacturer and its determination is left to the system
At this juncture it is prudent to reiterate that a fan running at a
particular speed can have an infinite number of operating points all
along its characteristic curve. The fan will interact with the system
to produce an operating point at the intersection of the system curve
and the fan curve. Note that it is the system in which the fan is
installed that will determine the operating point on the fan curve.
Thus it is vitally important that the system designer accurately
determine the system losses in order to ensure that the actual air flow
rate is as close as possible to the design air flow rate.